It is well known to add chelating agents to boiler water for the purpose of preventing scale formation on the internal surfaces of boiler tubes caused by hardness deposits. However, such agents are known to cause undesirable corrosion under certain conditions.
It has also been known to photometrically determine chelant level in industrial water by adding a second chelating agent and a color indicator to a water sample for photometrically making absorbance readings and comparing the absorbance value to a predetermined set of absorbance values plotted against ppm levels of chelant excesses or deficiencies.
It has also been known to treat industrial water and particularly boiler water with a product that includes a copolymer of acrylamide and acrylate and a copolymer of acrylic acid and sodium vinyl sulphonate which is sold by Nalco Chemical Company of Naperville, Illinois, under the trademark "TRANSPORT PLUS" such as Nalco 7200 and as disclosed in their U.S. Patent No. 4,457,847. It has also been known to manually test the level of such a polymer in the water by taking a sample, adding a reagent that will coact with only the acrylate component of the product and produce turbidity so that the reacting solution can be subjected to a photometric analysis. Such a test procedure depends completely upon the skill of the test operator.
With the increasing demand of industry for improved reliability and control, there is a need for automating testing procedures, and particularly with respect to determining the level of a water treatment product in boiler feedwater.
It has further been known to provide test equipment such as the pump colorimeter analyzers sold by the Hach Company of Loveland, Colorado. Other analyzers have also been made for measuring turbidity in solutions. However, no analyzer has been available for continually testing boiler feedwater for the level of a water treatment product of the type in the above patent.